Ivan I. Shevchenko

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It is suggested to derive formulae (dependences on symbolic parameters) by means of restoration upon a set of fixed exact numeric values of the parameters. The main tool is Pade interpolation. The problem of distortion of structure of restored expressions and, to some extent, the problem of verification of results are considered. A statistical treatment of(More)
The perturbed motion in the neighborhood of regular precession of a dynamically symmetric satellite on a circular orbit is studied. The " Norma " specialized program package [1,2], intended for normal-ization of autonomous Hamiltonian systems by means of computer algebra, is used to obtain normal forms of the Hamiltonian. A full catalogue of non-resonant(More)
Algorithms of numeric (in exact arithmetic) deduction of analytical expressions, proposed and described by Shevchenko and Vasiliev (1993), are developed and implemented in a computer algebra code. This code is built as a superstructure for the computer algebra package by Shevchenko and Sokolsky (1993a) for normalization of Hamil-tonian systems of ordinary(More)
The paper analyzes the time course of changes in the intake of staple foods in the Krasnoyarsk Territory in 1998-2005. It is shown that the ingestion of iodine-rich foods has not increased greatly and it is low and does not provide the population with this essential micronutrient. The actual content of iodine in the study samples of food and its raw(More)
We consider statistics of the disruption and Lyapunov times in an hierarchical restricted three-body problem. We show that at the edge of disruption the orbital periods and the size of the orbit of the escaping body exhibit Lévy flights. Due to them, the time decay of the survival probability is heavy-tailed with the power-law index equal to -2/3, while the(More)
The paper gives a brief analysis of the prevalence and trends of childhood morbidity in small towns of the Krasnoyarsk Territory. Morbidity in small towns is shown to be greater than the average territorial rate. The increase in overall morbidity in children is affected by the schooling environment where a child stay 6-8 hours daily and that ensures no(More)